An oil film flowing on water appears coloured due to interference. For observing this effect,the approximate thickness of the oil film should be:

What is the shape of the interference fringes formed on the screen due to a point source $P$,in the case shown here?

Which of the following produces coherent waves?

Imperfections in optical lenses can be observed with the help of

In a biprism experiment,a wavelength $\lambda$ is used to obtain an interference pattern. The fringe width is $W_1$ at a distance $D_1$ from the screen. When the screen is moved towards the biprism,the fringe width becomes $W_2$ at a distance $D_2$. The distance between the two virtual images of the slit is:

The following diagram is an arrangement to view the interference pattern produced by a wedge of liquid between a microscope slide and a glass block. The interference pattern obtained is made of equally spaced parallel fringes. The fringe separation (or fringe width) $\beta$ may be decreased by some of the following actions (Consider one change at a time).